Fixation plate system for dorsal wrist fracture fixation

ABSTRACT

A dorsal fracture is treated from the volar side by using a T-shaped plate opposite the fracture. The plate is positioned against the volar side of the radial bone, a plurality of bone screws secure the plate along a non-fractured portion of the radial bone, and a plurality of bone pegs extend from the plate and into the bone fragments of the fracture. A support portion of the plate is provided distal of the bone pegs and supports comminuted bone fragments. One or more channels are optionally provided in the plate to receive wires which are adapted to anchor distal bone fragments to the plate. The plate is adapted in strength and materials to withstand the large bending forces thereon.

[0001] This application is a continuation-in-part of U.S. Ser. No.09/735,228, filed Dec. 12, 2000, which is a continuation-in-part of bothU.S. Ser. No. 09/524,058, filed Mar. 13, 2000 and U.S. Ser. No.09/495,854, filed Feb. 1, 2000, each of which are hereby incorporated byreference herein in their entireties.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates broadly to surgical systems and methods.More particularly, this invention relates to a system and method forfracture fixation for a dorsal distal radius fracture.

[0004] 2. State of the Art

[0005] Fractures of the wrist are difficult to align and treat.Alignment and fixation are typically performed by one of severalmethods: casting, external fixation, interosseous wiring, and plating.Casting is noninvasive, but may not be able to maintain alignment of thefracture where many bone fragments exist. Therefore, as an alternative,external fixators may be used. External fixators utilize a method knownas ligamentotaxis, which provides distraction forces across the jointand permits the fracture to be aligned based upon the tension placed onthe surrounding ligaments. However, while external fixators can maintainthe position of the wrist, it may nevertheless be difficult in certainfractures to first provide the bones in proper alignment. In addition,external fixators are often not suitable for fractures resulting inmultiple bone fragments. In addition, external fixation is associatedwith reflex sympathetic dystrophy, stiffness, and pin complications.Moreover, with some fractures, movement of the wrist is an essentialpart of rehabilitation, and this movement is prevented by externalfixation. Interosseous wiring is an invasive procedure whereby screwsare positioned into the various fragments and the screws are then wiredtogether as bracing. This is a difficult and time consuming procedure.Moreover, unless the bracing is quite complex, the fracture may not beproperly stabilized.

[0006] Volar wrist fractures (Colles' fractures) have been treated witha volar plate and screw system. The volar plate is generally a T-shapedplate having a head portion and a body portion. The body portion hasholes along its length and the head portion has holes at its distal end.The holes are for receiving self-tapping bone screws therethrough. Inuse, the bone fragments of the volar wrist fracture are aligned and thebody portion of the plate is screwed to an integral portion of theradius proximal of the fracture. Screws are then provided through theholes in the head portion to define a stabilizing framework about thefractured bone fragments heal.

[0007] Dorsal wrist fractures have also been treated with a plate, butthe plate is attached to the dorsal side of the radius. Referring toprior art FIG. 1, dorsal fixation has previously used a relatively thinplate 10 secured to the dorsal side of the radius 12. Like the volarplate, the dorsal plate 10 has a body portion 14 and a head portion 16.Holes 18 are provided in the both the body and head portions, and screws20 extend therethrough into the radius 12 to compress the plate 10against the bone and stabilize the fracture. The plate design, in termsof strength and support, has not been critical, as the forces on thedorsal plate from the tendons and bending forces are not substantiallylarge. In fact, there is substantially no bending load on a dorsalplate. However, use of the dorsal plate commonly results in extensortendon problems, as the extensor tendons run close to the bone surfaceand are irritated by the plate. In addition, it is common in distalradius fractures for one or more fragments, e.g., the radial styloidfragment, the volar dipunch fragment, and/or the dorsal dipunchfragment, to become loosened or detached from the bone system. It isnecessary to stabilize these fragment to prevent further movementrelative to the desired stabilizing arrangement and prevention ofdesired healing. Yet, stabilization of this bone with a dorsal plate isimpractical, as the fragments are located on the opposite side of thebone from the dorsal plate. As such, a new dorsal wrist fracturefixation system is desired.

SUMMARY OF THE INVENTION

[0008] It is therefore an object of the invention to provide a fracturefixation system for a dorsal wrist fracture.

[0009] It is another object of the invention to provide dorsal fracturefixation in a manner which does not cause extensor tendon irritation.

[0010] It is also an object of the invention to provide a dorsalfracture fixation system which stabilizes distal radius bone fragments.

[0011] It is a further object of the invention to provide a dorsalfracture fixation system which provides stability and support to thefracture to overcome the forces from the tendons and rotational forcesat the fracture.

[0012] In accord with these objects, which will be discussed in detailbelow, a dorsal fracture is treated from the volar side by using afixation plate. The plate is generally a T-shaped plate defining anelongate body portion, a head portion transverse to the body portion,and a neck portion therebetween. The neck portion defines a fixed anglebetween the head and body portions. The plate also includes a first sideintended to contact the bone, and a second side opposite the first side.The plate is substantially thick and rigid, and made of a high strengthmaterial such as titanium to resist the high bending loads to which avolar plate is subject in order to stabilize a dorsal fracture.

[0013] The head portion includes a plurality of threaded peg holes forreceiving pegs therethrough. The center of the peg holes are preferablyarranged along a line, with the axis of each peg hole preferably beingin an oblique orientation relative to the axes of the other peg holessuch that pegs therethrough are obliquely oriented relative to eachother. According to one preferred aspect of the invention, at least halfof the head portion extends on the distal side of the line defining abuttress on which to support bone fragments. The body portion includes aplurality of screw holes for the extension of the bone screwstherethrough.

[0014] According to another preferred aspect of the invention, one ormore channels extend in the first side of the head portion of the plate,preferably substantially parallel to the body portion. One or more wiresare partially provided within the channels, and extend distally from thehead portion of the plate to provide additional support for one or morebone fragments. The wires includes a distal means for anchoring to oneor more bone fragments, and are coupled to their proximal ends of theplate.

[0015] According to another embodiment of the volar plate, the buttresscomprises a plurality of tines, which may be bent to access and supportdistal articular fragments of a fracture.

[0016] In use, the plate is positioned with its first side against thevolar side of the radius and bone screws are inserted through the bonescrew holes into the radius to secure the volar plate to the radius. Thebone fragments of the dorsal fracture are then aligned. A drill drillsholes through the peg holes and into the bone fragments. The pegs arethen inserted through the peg holes and into the holes in the bone, andthreadably locked in position, with the head portion buttress supportingthe bone fragments. The optional wires and tines also assist in bonefragment support. The structure of the plate, as well as the ability offragment to slide along the bone pegs permits the plate to withstand theforces on the plate and provide a stabilizing structure whichfacilitates healing.

[0017] Additional objects and advantages of the invention will becomeapparent to those skilled in the art upon reference to the detaileddescription taken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Prior art FIG. 1 is a dorsal wrist fracture and a prior artsystem for dorsal fracture fixation;

[0019]FIG. 2 is a top volar view of a right hand volar plate for dorsalwrist fracture according to a first embodiment of the invention;

[0020]FIG. 3 is a side view of the plate of FIG. 2, shown with bonescrews and pegs positioned therein;

[0021]FIG. 4 is a bottom view of the plate of FIG. 2; the invention;

[0022]FIG. 5 is an enlarged side elevation of a first embodiment of apeg for use with the plate of the invention;

[0023]FIG. 5A is an enlarged side elevation of a second embodiment of apeg for use with the plate of the invention;

[0024]FIG. 6 is an illustration of the first embodiment of the plateaccording to the first embodiment of the invention provided in situ atthe volar side of the radius for the treatment of a dorsal wristfracture;

[0025]FIG. 7 is an illustration of the hypothetical use of a prior artvolar plate used at the volar side of the radius for the treatment of adorsal wrist fracture;

[0026]FIG. 8 is a bottom view of a volar plate and wire according to asecond embodiment of the invention;

[0027]FIG. 9 is an illustration of the use of the volar plate and wireof FIG. 8 for the volar side treatment of a dorsal wrist fracture;

[0028]FIG. 10 is a bottom view of a volar plate and anchor according toa third embodiment of the invention;

[0029]FIG. 11 is an illustration of the use of the volar plate and hookof FIG. 10 for the volar side treatment of a dorsal wrist fracture; and

[0030]FIG. 12 is a bottom view of a volar plate according to a fourthembodiment of the invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Turning now to FIGS. 2 through 4, a first embodiment of a volarplate system for dorsal wrist fracture fixation generally includes asubstantially rigid T-shaped plate 100. The plate includes a pluralityof holes 102 which receive self-tapping bone screws 104 to secure theplate 100 along a non-fractured portion of the radial bone. The platealso includes a plurality of threaded peg holes 106 which receive pegs108 therein and are adapted to extend into bone fragments of thefracture.

[0032] The T-shaped plate 100 defines a head portion 110, an elongatebody portion 112, and a neck portion 114 therebetween at which the headand body portions are angled relative to each other. A preferred angleis approximately 23° and the curvature of the neck portion is preferablyat a radius of approximately one inch. The plate also includes a firstside 120 which is intended to contact the bone, and a second side 122opposite the first side. The first side 120 at the head portion ispreferably planar, as is the first side at the body portion. As the headportion and body portion are angled relative to each other, the firstside preferably defines two planar portions connected by the curved neckportion.

[0033] The plate 102 preferably has a thickness of approximately atleast 2 mm at the head portion, and 2.5 mm along the body portion. Amore preferred plate thickness is 4 to 6 mm, or more, at each of thebody and head portions. The distal end 124 of the head portion ispreferably tapered to provide a low distal profile and terminates at anedge 126. In addition, according to one preferred embodiment and not byway of limitation, the plate preferably has a width of 10 mm at the bodyportion, 11 mm at the neck portion, and 23 mm across line L of the headportion. The plate 102 is preferably made from a titanium alloy, such asTi-GA1-4V.

[0034] The head portion 112 of the plate includes the threaded peg holes106. In the preferred embodiment there are four threaded peg holes 106a, 106 b, 106 c, 106 d (FIG. 4). The peg holes are preferably linearlyarranged along the head portion 114, and are optionally provided suchthat the adjacent peg holes are provided further distally in a medial tolateral direction along the second side. As such, the centers of the pegholes lie along a line L (FIG. 4). According to another preferred aspectof the plate, each peg hole preferably defines an axis (axes A₁, A₂, A₃,and A₄ in FIG. 4) which is oblique (non-parallel) relative to the otherpeg holes such that pegs inserted therethrough are obliquely orientedrelative to each other such that a fan-like shape is defined by the pegs(see FIG. 3). More particularly, and more preferably, the axes of thepeg holes are angled in two dimensions (medial/lateral andproximal/distal) relative to each other; i.e., the pegs once insertedinto the peg holes are also angled in two dimensions relative to eachother. Preferred orientations of the axes of the peg holes are describedin detail in previously incorporated U.S. Ser. Nos. 09/495,854 and U.S.Ser. No. 09/524,058. According to a preferred aspect of the invention,preferably at least half of the head portion (portion 114 a) extends onthe distal side of the line defined by the linear arrangement of pegholes (between the line L and the distal edge 126). This distal headportion 114 a defines a buttress on which to support bone fragments, asdescribed in more detail below.

[0035] The body portion 112 includes the plurality of screw holes 104for the extension of the bone screws therethrough. Preferably one of thescrew holes 102 a (FIG. 2) is oblong.

[0036] Referring to FIG. 5, each peg 108 has a non-tapered threaded head127 and a substantially cylindrical shaft 128. The shaft 128 may berelatively smooth and non-threaded, as described in detail in previouslyincorporated, U.S. Ser. No. 09/524,058. Alternatively, referring to FIG.5A, the peg 108 a may include a shaft 128 a provided with threads 129 a.If the peg 108 a includes a threaded shaft 128 a, the threads 129 a onthe shaft are preferably of a different pitch than the threads on thehead 127 a. For example, the shaft 128 a may include a pitch of twentyfour threads per inch to aid in compression, while the head 127 a mayinclude a pitch of forty threads per inch for engagement in the pegholes. The pegs are preferably 2 mm in diameter.

[0037] Referring now to FIG. 6, after a dorsal wrist fracture, the volarside of the wrist is opened (with tissue and muscle retracted from thevolar side of the radius bone) and the plate 100 is positioned with itsfirst side 120 against the volar side of the radius. A bone screw 104 ais inserted through the oblong bone screw hole 102 a (FIG. 2), but notcompletely tightened, to attach the plate to the radius. The plate 100is moved relative to the screw 104 a, and aligned relative to the radiusand the fracture. The screw 104 a in hole 102 a is then tightened, andother screws are also provided in the other screw holes, as needed, tosecure the plate to the radius. The taper at the distal end 124substantially eliminates contact between the plate and the tendonsthereabout, thereby preventing the tendon abrasion which commonlyoccurred with prior art dorsal plates.

[0038] The bone fragments 130, 132 (with 132 being the volar dipunchfragment) of the fracture are anatomically aligned as best as possible.Holes are then drilled through the peg holes, in alignment with therespective axes A₁, A₂, A₃, A₄ (FIG. 4), and into the fragments andinterstices therebetween.

[0039] The pegs 108 are then inserted through the peg holes 106 (FIG.2), and the heads of the pegs are threadably engaged in the plate. Thepegs 108, extending through the oblique-axis peg holes are positionedimmediately below the subcondylar bone of the radius. It is noted thatthe dorsal wrist fracture is a dorsally unstable fracture. The pegs 108,when not threaded, function as rails and permit the unstable distal bonefragments to move with one degree of freedom; that is, the fragments mayonly slide toward the volar side. Furthermore, in accord with theinvention, the buttress 114 a limits the sliding movement and providessupport for comminuted fragments, such as the volar dipunch 132, distalof the pegs.

[0040] Placing the plate 100 at the volar side for a dorsal fracturesubjects the plate to substantially higher forces than a dorsal plate.The force F_(T) of the tendons at the wrist places compressive forces onthe plate, and movement of the wrist during postoperative healing andrehabilitation places high bending loads F_(B) on the plate,particularly at the screw 104 b closest the head portion. These forcesare accommodated in at least two ways. First, as noted above, bonefragments are able to slide upon the pegs, rather than being fixed tothe pegs. The advantage of this is discussed below with reference toFIG. 7. Second, as discussed below with respect to plates from othermanufactures, the plate of the invention is designed to be stronger(substantially thicker and of stronger materials) than prior art plates.This increases the ability of the plate to withstand the bending forcesto which it is subject.

[0041] Referring to FIG. 7, for comparison purposes, it is shown that ifa conventional volar or dorsal plate 200 is used according to the methoddescribed above, the same results would not be provided. Conventionalplates use all screws 204 and no pegs. Bone fragments, e.g., 230, cannotslide upon the screws, as the screws tap into the bone fragments and fixthe fragments in a location relative to the plate. This does to permitforces to be dissipated via sliding movement of the fragments and, assuch, the plate is subject to much greater bending loads F_(B) inaddition to the compressive loads by the tendons F_(T). Also,conventional plates do not have a buttress at the head portion inaddition to pegs. As such, there is no support for any movable andunstable bone fragments distal of the screws, e.g., volar dipunch 232.Furthermore, the plate is substantially thinner and not constructed ofmaterials adapted to withstand the forces on the volar side of thedorsal fracture. For example, the TT™ plate or volar-T™ plate availablefrom Synthes of Paoli, Pa., is made of a titanium alloy, but only 2 mmthick and 4 mm wide. The plate of the present invention is 3.5 timesstronger than the Synthes plate, as measured by the ultimate load tofailure. The SCS™ plate (subcondral support plate), available fromAvanta of San Diegeo, Calif., is made of weaker stainless steel, and hasa thickness of 1.5 mm and a width of 11 mm. Such plates are not suitedfor the forces the volar side treatment of a dorsal wrist fracture asplate failure would be relatively high.

[0042] Turning now to FIG. 8, a second embodiment of a plate 300,substantially similar to the first embodiment (with like elements havingreference numerals incremented by 200) is shown. The first side 320 ofthe head portion 314 of the plate 300 is provided with two channels 340,342, one on either side of the medial-most peg hole 306 a, which extendthe length of the head portion. The channels 340, 342 are sized toreceive a K-wire 344 therein. The K-wires is surgical grade wirepreferably having a diameter of 0.062 inch. The K-wire 344 is preferablyU-shaped, with the closed loop 346 provided distally and the free ends348, 350 extending proximally through the channels and out thereof toextend along a length of the body portion 312 of the plate.

[0043] Referring to FIG. 9, the U-shaped K-wire 344 is provided in thechannels as described above, and the plate is then attached to theradius as described above with respect to FIG. 6. The distal locationloop can be adjusted by movement of the free ends to cause the loop tolie under one or more fragments, e.g., 352, 354 which is desired to bestabilized. A screw 356 having a head sized greater than the loop 346 isthen positioned within the loop and tapped into the fragments to securethe fragments and K-wire together. The free ends 348, 350 of the wireare then tied off or otherwise secured to maintain the position of theloop relative to the plate. As such, a means is provided for stabilizingfragments located distal of the buttress by supporting and retaining thefragments.

[0044] Turning now to FIG. 10, a third embodiment of a plate 400,substantially similar to the second embodiment (with like elementshaving reference numerals incremented by 100 relative thereto) is shown.A channel 440 is provided in the head portion 414 of the plate 400 andextends only partly along the length of the head portion. A hole 460 isprovided at the proximal end of the channel and extends to the secondside of the plate. A single K-wire 444, provided with a distal anchor(or hook) 446 and a proximal end 448, extends within the channel andthrough the hole 460.

[0045] Referring to FIG. 11, the anchor 446 of the K-wire 444 isimpacted into a fragment 452. If not previously threaded, the proximalend 448 of the wire 444 is then fed into the channel 440 and through thehole 460. The plate is then attached to the radius as described abovewith respect to FIG. 6. The wire 444 is then placed under tension (toconstrain the distal fragment 452) and the proximal end 448 is secured,e.g., in a screw hole about the head of a screw.

[0046] Turning now to FIG. 12, a fourth embodiment of a plate 500,substantially similar to the first embodiment (with like elements havingreference numerals incremented by 400) is shown. The head portion 510distal of the peg holes 506 includes a plurality of tines 580. The tines580 are preferably tapered in thickness relative to a remainder of thehead portion, permitting each to be independently bent and substantiallypreventing tendon contact. As such, a configurable and individuallycustomizable buttress structure useful in the support of distalfragments at a particular location is provided. Each tine is preferablyapproximately 7 mm in length and 2 mm in width, although other suitabledimensions (bendable by the physician, yet providing anatomical support)can be used. In use, the tines are bent by the physician into aconfiguration which will access and support the distal articularfragments. The plate is then attached to the radius as described abovewith respect to FIG. 6. Alternatively, though less desirably, the platemay first be attached to the radius and the tines then bent.

[0047] There have been described and illustrated herein embodiments of asystem and method for stabilizing dorsal wrist fractures using a volarplate. While particular embodiments of the invention have beendescribed, it is not intended that the invention be limited thereto, asit is intended that the invention be as broad in scope as the art willallow and that the specification be read likewise. Thus, whileparticular materials for the elements of the system have been disclosed,it will be appreciated that other materials may be used as well. Inaddition, while a particular number of screw holes in the volar platesand bone screws have been described, it will be understood anothernumber of screw holes and screws may be provided. Further, fewer screwsthan the number of screw holes may be used to secure to the volar plateto the radius. Also, fewer or more peg holes and bone pegs may be used,preferably such that at least two pegs angled in two dimensions relativeto each other are provided. Moreover, while the pegs are preferablylinearly arranged, it will be appreciated that they may be non-linearlyarranged, and may lie along a curve such as a parabolic curve, asdescribed in previously incorporated U.S. Ser. No. 09/495,854 and U.S.Ser. No. 09/524,058. As such, the buttress portion is defined as thearea distal the peg holes, whether or not the peg holes lie along astraight line. In addition, the pegs may be adjustable relative to thepeg holes such that each peg can be independently fixed in a selectableorientation, as described in previously incorporated U.S. Ser. No.09/735,228. Also, while a particular preferred angle between the headportion and body portion has been disclosed, other angles can also beused. While a right-handed plate is described with respect to the firstembodiment, it will be appreciated that the volar plate for dorsalfixation may be formed in either a right- or left-handed model, with theleft-handed model being a mirror image of the right-handed modeldescribed. Also, while two plate channel and K-wire assemblies have beendisclosed for securing distal bone fragments to the plate, it will beappreciated that more than two channels and multiple K-wires may also beused, and that the channels may extend the length of the head portion orextend only part way, with an exit provided for the K-wire or K-wires.Furthermore, while two K-wire anchoring means having been disclosed(hooks and screws), it will be appreciated that other means foranchoring the K-wire into a bone fragment, e.g., nails, staples,additional K-wires, can be used as well. Also, other types of wiresother than K-wires may be utilized. In addition, while preferreddimensions for a plate have been provided, it will be appreciated thatother dimensions providing the substantially strong structure requiredto withstand the forces to which the plate when the plate is used in themanner of the method of the invention may also be used. It willtherefore be appreciated by those skilled in the art that yet othermodifications could be made to the provided invention without deviatingfrom its spirit and scope as claimed.

1. A fixation plate for volar side fixation of a dorsal fracture,comprising: a substantially rigid plate including a distal head portionand a proximal body portion angled relative to said head portion, saidhead portion defining a plurality of threaded peg holes adapted toindividually receive fixation pegs therein, said plurality of threadedpeg holes dividing said head portion between distal and proximalportions, said distal portion being larger than said proximal portion,said distal portion having a distal edge tapering in thickness, and saidbody portion including at least one screw hole.
 2. A fixation plateaccording to claim 1, wherein: said peg holes are linearly arranged. 3.A fixation plate according to claim 1, wherein: said head portionincludes a plurality of tines.
 4. A fixation plate according to claim 1,wherein: said plate has a thickness of at least 4 mm.
 5. A fixationplate according to claim 4, wherein: said plate is made from a titaniumalloy.
 6. A fixation plate according to claim 1, wherein: said plate hasa thickness of approximately 4 mm to approximately 6 mm.
 7. A fixationplate for volar side fixation of a dorsal fracture, comprising: asubstantially rigid plate including a distal head portion and a proximalbody portion angled relative to said head portion, said head portiondefining a plurality of threaded peg holes adapted to individuallyreceive fixation pegs therein, and also provided with at least onechannel extending at least partially along a length of said head portionand not intersecting any of said threaded peg holes, said body portionincluding at least one screw hole.
 8. A fixation plate according toclaim 7, wherein: said at least one channel is not aligned with any ofsaid threaded peg holes.
 9. A fixation plate according to claim 7,wherein: said at least one channel extends from a distal end of saidhead portion to a terminal location relatively proximal thereto, and atsaid terminal location each said at least one channel is provided with ahole extending through said plate.
 10. A fixation plate for volar sidefixation of a dorsal fracture, comprising: a substantially rigid plateincluding a distal head portion and a proximal body portion angledrelative to said head portion, said head portion defining a plurality ofthreaded peg holes adapted to individually receive fixation pegstherein, and said body portion including at least one screw hole,wherein said plate has a thickness of at least 4 mm and is made from atitanium alloy, and said head portion includes a tapered distal edge.11. A fixation plate according to claim 10, wherein: said plate has athickness of approximately 4 mm to approximately 6 mm.
 12. A fracturefixation system, comprising: a) a substantially rigid plate including adistal head portion and a proximal body portion angled relative to saidhead portion, said head portion defining a plurality of threaded pegholes adapted to individually receive fixation pegs therein, and saidbody portion including at least one screw hole; and b) at least one wireto secure a bone fragment of the dorsal fracture to said plate.
 13. Asystem according to claim 12, wherein: said wire is U-shaped.
 14. Asystem according to claim 12, wherein: said wire includes an anchoringmeans for anchoring into bone.
 15. A system according to claim 12,wherein: said plate includes at least one channel in which to partiallyreceive said at least one wire.
 16. A system according to claim 15,wherein: said at least one channel is not aligned with any of saidthreaded peg holes.
 17. A system according to claim 15, wherein: said atleast one channel extends from a distal end of said head portion to aterminal location relatively proximal thereto, and at said terminallocation each said at least one channel is provided with a holeextending through said plate.
 18. A system according to claim 12,further comprising: c) a plurality of pegs adapted to be threadablyreceived in said threaded peg holes; and d) at least one screw adaptedto be received through the at least one screw hole and tap into bone.